Asking about the question below. please give me detail explanations and right answers. thanks so much!

Question:

a) A company plans to use 4 hours to produce 1 unit but uses actually 5 hours per unit. Was the company more efficient or less efficient in their use of labour hours?

b) If a company plans 2 hours per units at a cost of $15 per hour and produces 200 units, how much is allocated as variable manufacturing costs during the period?